There are plenty of PDF viewers for iOS and a handful of editors, but nothing is quite so simple-to-use and feature-rich as PDFExpert. While some of the competition comes close, it's our pick for the best when working with PDFs on your iPhone.

Where It Excels

PDFExpert is about as close as you're going to get to a desktop-class PDF viewer and editor on your phone. It has a really nice, simple interface for bringing up your documents. You can get your documents on your iPhone (or iPad) by syncing through iTunes, copying from iDisk, syncing with Dropbox, and a few other services. The annotation tools are really phenomenal, with multiple highlighting methods, arrows, text, and several other ways to mark up your documents. And I say documents because PDFExpert can handle more than just PDFs. While that's the feature in the name, it'll work with iWork documents, Microsoft Office files, Powerpoint presentations, text files, images, music, and video. While you don't need all of that in a PDF viewer, it basically doubles as a file management app and that's a nice bonus. Overall, PDFExpert is really solid and has a great, comprehensive feature set. PDF-wise, it really does everything you could possibly need to do on a touchscreen device.

Where It Falls Short

PDFExpert is pretty expensive. It's $10 for iPhone and $10 for iPad, so if you want both you have to pay twice. This is on top of it already being one of the most expensive PDF viewers/editors that you can get on iOS. While great software should warrant the price, it gets a little frustrating when you're paying that much money for multiple devices. Normally you could just stick with one device, but a PDF viewer/editor is one of those apps that works significantly better on a tablet thanks to the extra screen real estate. If you're a heavy iPhone and iPad user, you might prefer to use the iPad whenever possible but occasionally need to use the iPhone. Personally, I'd rather just deal with PDFs on my laptop but if your iDevices are highly integrated into your workflow then you're probably going to want both apps. And that's an expensive problem.

The Competition

The most obvious competition is GoodReader ($5), which is nearly as good at half the price. The only thing that PDFExpert has over GoodReader is the ability to handle PDF forms. If you don't need to fill out forms on your iPhone or iPad, this is probably a better alternative. You can pull files from virtually anywhere, it handles PDF annotation well, and it can view a lot more than PDFs.

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PDF Reader Pro ($3) is a slightly cheaper option that provides you with pretty much all the features of PDFExpert and then some. For example, it'll actually scan documents. On paper it looks like a much better app, but in use you'll end up spending more time dealing with the way it handles files and moves through modes of annotation. It also seems to render PDFs slower than other apps. That said it's definitely not bad, and you get a lot for your $3. It's a hybrid app and a great deal anyway, so if you don't want to fork over the cash for PDFExpert and want even more features, it's a pretty solid option.

For viewing purposes, Dropbox (Free) and iBooks (Free) are actually pretty nice to use. iBooks is great if you already use it for books and are trying to consolidate. Dropbox is great because it requires zero effort to sync files. Both are just readers, however, so they may not be your best bet.

Obviously there are other PDF viewers/editors for iOS. If there's one you love that we didn't mention, share it in the comments.

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